This 1/2 hertz high selectivity filter was found in the December 1990 issue of Radio Electronics magazine. The source must be symmetrical. The capacitors can be changed for other frequencies.
From a 90s Popular Electronics, this circuit emits pulsating signals for different types of...
Found in a Popular Electronics from the 90's, this circuit converts a 40 V symmetrical source to a 5...
This circuit generates frequencies determined by R3 and C1. We found it in the Radio Electronics magazine...